Delphi VirtualStringTree OnGetHint

I want to show hint when cell text is already fully shown.
so, on form's OnCreate

procedure TForm1.FormCreate(Sender: TObject);
begin
  VirtualStringTree1.HintMode := hmHint;
  VirtualStringTree1.ShowHint := True;
end;

and OnGetHint

procedure TForm1.VirtualStringTree1GetHint(Sender: TBaseVirtualTree;
  Node: PVirtualNode; Column: TColumnIndex;
  var LineBreakStyle: TVTTooltipLineBreakStyle; var HintText: string);
begin
  HintText := IntToStr(Node.Index);
end;

but nothing happens.

OnGetHint event handler is not fired and even TBaseVirtualTree.CMHintShow breakpoint is not working.

what can I supposed to do?

I`m using delphi xe3, virtualtreeview 5.2.1.

Thanks for the answer.

I followed your guide.

Application properties

ShowHint := True // I checked but set to true on OnCreate explicitly

Vst propertiess

Hint, e.g. 'Hint for the whole VST' // yes, add meaningless hint
HintAnimation, e.g. hatNone
HintMode, e.g. hmHintAndDefault // as you see, on OnCreate
ShowHint, True// as you see, on OnCreate
ParentShowHint, as needed, use False if you don't know // yes

Vst events to implement

OnDrawHint() // yes
OnGetHint() // yes
OnGetHintSize() // yes

but nothing changed.
OnGetHint, OnGetHintSize, OnDrawHint are not fired at all.
(when HintMode set to hmToolTip and text is not fully shown, OnGetHint is fired only)

And yes, I read that documentation VirtualTreeView.pdf.
but all description about Event is exactly same as your quote.
I need more explanation.

Update:

Very weird thing.
I have tested this other PCs.

My PC Windows 10 xe3 vst 5.2.1

not work

PC 1 Windows 10 xe3 vst 5.2.1

compile and execute // work
compile on My PC, copy and execute // work

PC 2 Windows 10

compile on My PC, copy and execute // work

What????
the code was not the problem.
I don't know why and even where to start.

anyway, I really thanks about answer and accept it.
if anyone knows about this weird thing, please let me know.
if I find out, I will update.

Several properties and event handlers must be in place/implemented for node specific hints to show. The following should get you started:

Application properties

ShowHint := True

Vst properties

Hint, e.g. 'Hint for the whole VST'
HintAnimation, e.g. hatNone
HintMode, e.g. hmHintAndDefault
ShowHint, True
ParentShowHint, as needed, use False if you don't know

Vst events to implement

OnDrawHint()
OnGetHint()
OnGetHintSize()

From the documentation:

Use an event handler for OnDrawHint() to draw the hint or tooltip for the given node. You must implement this event and OnGetHintSize() to get a hint at all.

Look on the net for VirtualTreeView.pdf for documentation